Process of making artificial filaments and product thereof



Patented Oct. 18, I932.

CAMILLE oeuvres, or New YORILN. "2., AND ILLIAM WHITEHEAD, onCUMBERLAND.

'IYLALRYLAND, Ass enons 'ro oE NEsE CORPORATION 01?. AMERICA, Aoonron'rIon,

or DELAW R rnoonss or MA ING No Drawing. Application filed SeptemberThis invention relates'to'the production of artificial filaments, yarns,bristles and'the like made of or containing cellulosic material. Anobject of our invention'is to produce filaments of cellulosic material,which filaments contain lumens or other hollow-spaces reim 'notherobject of'ourinvention is to "produce hollow filaments or bristles fromsolutions of cellulosio material by forming the same at a lower ratethan has been previously employed. Other objects of our invention willappear from the following detaileddescription.

In the process of making artificial filaments is from cellulosicderivatives as now practiced, solutions of celluloslc' materlal areextruded orifices :of a spinnerette,

through circular either into a preclpitating bath, as in wet spinning,or into an evaporative atmosphere, as in dry spinning, and the filamentsthus formed are drawn oil at a comparatively high speed, ranging from 25to 200 meters of length of filament per minute. The filaments thusformed, however, have a solid cross section. We have found that if therate of spinning is materially reduced, low spaces therein ma be formed.Such hollow filaments are pre erable to the solid-filaments, since for agiven weight they have greater covering power than the solid filaments.

In accordancewith our'invention, we pre pare filaments having lumens orhollow spaces therein by the wet or dry spinning of solutions containingcellulosic derivatives at a much lower rate than has been previouslyemployed. 7

By the process of our invention, filaments,

yarns, bristles or artificial horse-hair, etc. may be made. of a veryfine denier, on the order of less than 2 to 15 or more denier, whichfilaments may be associated together to form artificial yarns.

This process may be employed for preparing strands or single filamentsof much heavier denier such as 100, 300 to 1500'denier or more,

thus forming stifi' bristles or artificialhorsehair that maybe used inbrushes that are adapted for toilet use. The filaments may s, 1928.Serial No. 304,804.

"or any other suitable material;

filaments having hol-' ride, ethylene dichloride-and ethyl or methylalcohol.

The filaments formed maybe ARTIFICIAL II II II'rsANDrnoDI cr: 'rnnimor,

also be employed for making braids, ribbons This invention may beapplied for makin filaments orbristles by the viscose metho wherein asolution .of viscose is extruded through spinnerettes into an aqueousbath containing a precipitating agent such' as an acid.

The invention is'eminentlysuited for mak lng filaments from organicderivativesof cel lulose. Examples of organic derivatives of .celluloseare organic esters of cellulosesuch as cellulose acetate, celluose'formate, cellulosepropionate, cellulosebutyr'ate; or'celluloseethersysuch as ethyl cellulose, methyl cellulose or of benzylcellulose;- Tliese or- ,ganic derivatives of cellulose are'dissolved in.

a suitable solvent and the solution'extruded through orifices or aspinnerette, either into a bath containing a liquid which causesprecipitation of the cellulose derivativefrom the solution, or intoa dryingand evaporative' atmosphereas in dry spinning;

The sol-vents employed formakin'g solutionsof the organic derivatives ofcellulose maybe any suitable ones ,examples ofwhich a reaacetone,acetone and water, methylene chloride and ethyl alcohol, ethylenedichloalcohol (ethyl or methyl) ,rchloroform, or chloroform and As tothe rate'of spinning, this is prefl erably. on the order'of 0.025 to 0.1to5meters 'er' minute or more, dependin ofithe filaments to be produce.1 I s Thesize of theiorifices throughiwhich'the spinningsolution'iisiextruded will-vary with the heaviness of the filamentdesired. More'- over, the speed at which'the filaments are 96 thefilamentto be formed; i. e.- the heavier the V spun will vary inverselywith the weight of filamentto be, formed, the slowerthe rate "ofspinning.f..i

jon' thesize I The'filament after formation is preferably 1 drawn outwhile it still-retains some of the solvent ingorde'r to increaseitslength.

so'drawingou't, filaments of superior tenac ty: areproduced.-

lumens or hollow spaces: therein as shown by RT he filament stormed ourprocesi haive an examination of the cross section thereof,

whichhas distinct holes.

While we do not limit ourselves to this theory, we believe that theformation of hollow filaments by our process is due to the fact thatbecause of the low' rate of spinning, the spinning solution afterissuing from the jets of the spinnerette first starts to dry or skin atthe surface only, as in dry spinning, .or coagulate at the surface as inwet spinning, before the interior of the filament sets. Subsequently theinterior of the filament dries or coagulates with some shrinkage, whichowing to the previous formation of the solid hollow skin or shell of thefilament, causes the formation of hollow spaces. j a

In order further to illustrateour invention without limiting'the scopethereof, the

following specific example is given.

Example The following is a description of a method of preparing bristleshaving hollow spaces therein. A solution is made by dissolving one partof an acetone soluble cellulose acetate having an actyl value of 54.5%in 4: parts and 5% water.

The solution is extruded through a spinnerette having one or moreorifices of 0.8 mm. diameter into air, carbon dioxide or other inert gashaving a temperature of 40 to 45 C. The filaments thus formed are drawnoff by a roller at the rate of 0.1 meters per minute. As a result ofthis process filaments or bristles are ob tained that have a denier ofapproximately 1300, which bristles have lumens or hollow spaces therein.I

It is to be understood that the foregoing detailed description is givenmerely by way of illustration and that many variations maybe'madetherein without departing from the spirit of ourrin'vention.Having described our invention what we claim and desire to secure byLetters Patentis:'-

1.-Process of forming hollow filaments, bristles and the like comprisingextruding a solution of an organic derivative of cellulose in a volatilesolvent through orificesof a of a solvent mixture containing 95% acetone7 spinnerette into an. evaporating atmosphere heated to a temperaturebelow the boiling point of the solvent employed in the solut1on wherebysolid cellulosic filaments are formed and drawing off the filament atsuch slow rate that the solvent evaporates at the surface of thefilaments first sufiiciently to form asohd skinprior to the substantial1 evaporation of the solvent in the interior of the filaments, wherebyupon the evaporation of t e solvent inthe interior of the filamenthollow filaments are formed. i

2. -rocess of forming hollow filaments, brlstles 1 and the likecomprising f extruding an evaporative atmosphere of prior to thesubstantial evaporation ofthe solvent in the interior of the filaments,whereby upon the evaporation of the solvent in the interior of thefilament hollow'filaments are formed. I '3. Process of forming hollowfilaments comprisingextruding a solution of cellulose acetate in avolatile solvent through the orifices of a spinnerette into anevaporative atmosphere heated to atemperature below theboiling point ofthe volatile solvent and drawing ofl the filaments thus formed at a rateof less than 5 meters per minute.

In testimony whereof, we have hereunto subscribed our names.

' CAMILLE DREYFUS.

WILLIAM WHITEHEAD.

